The research work proposed contains two possible methods of detection of experimental and human colon cancer. Retinoic acid-binding protein has been presently detected in large amounts in two highly metastatic murine colon tumors, whereas this protein was below the limits of detection in two nonmetastatic colon tumors as well as in normal colon. We will standardize methods to detect RABP in tissues with metastatic foci of colon tumor. The limits and sensitivity of detection of the binding protein will be improved; assays and quantitation of the protein will be made on an approximate cell number basis. Analysis of the human colon tumor specimens and normal colon tissues for the binding protein will be carried out in order to evaluate a method for specific detection of human malignant tumor. Attempts to elucidate the role of this protein at genetic level in a colon tumor will be undertaken. A general physicochemical characterization of the binding protein from multiple sources will be assessed. Exudates from transformed cells, in contrast to the normal cells, give rise to elevated fibrinolytic activity. The cell factor (activator) contributing to this activity will be assayed by making the primary cell cultures of experimental tumors, particularly colon tumors. The rate of appearance of the activator due to metastasis of tumor cells into the lung and other tissues will be evaluated. About 100 samples of human colon tumors (malignant and benign), tissues around tumors and normal colon specimens will be tested for their fibrinolytic activity, to determine whether enhanced activator release is an essential enzymatic change associated with human malignant large bowel cancers.